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[emacs.git] / lisp / strokes.el

;;; strokes.el --- control Emacs through mouse strokes

;; Copyright (C) 1997 Free Software Foundation, Inc.

;; Author: David Bakhash <cadet@alum.mit.edu>
;; Maintainer: David Bakhash <cadet@alum.mit.edu>
;; Keywords: lisp, mouse, extensions

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;; This is the strokes package.  It is intended to allow the user to
;; control Emacs by means of mouse strokes.  Once strokes is loaded, you
;; can always get help be invoking `strokes-help':

;; > M-x strokes-help

;; and you can learn how to use the package.  A mouse stroke, for now,
;; can be defined as holding the middle button, for instance, and then
;; moving the mouse in whatever pattern you wish, which you have set
;; Emacs to understand as mapping to a given command.  For example, you
;; may wish the have a mouse stroke that looks like a capital `C' which
;; means `copy-region-as-kill'.  Treat strokes just like you do key
;; bindings.  For example, Emacs sets key bindings globally with the
;; `global-set-key' command.  Likewise, you can do

;; > M-x global-set-stroke

;; to interactively program in a stroke.  It would be wise to set the
;; first one to this very command, so that from then on, you invoke
;; `global-set-stroke' with a stroke.  likewise, there may eventually
;; be a `local-set-stroke' command, also analogous to `local-set-key'.

;; You can always unset the last stroke definition with the command

;; > M-x strokes-unset-last-stroke

;; and the last stroke that was added to `strokes-global-map' will be
;; removed.

;; Other analogies between strokes and key bindings are as follows:

;;    1) To describe a stroke binding, you can type

;;       > M-x describe-stroke

;;       analogous to `describe-key'.  It's also wise to have a stroke,
;;       like an `h', for help, or a `?', mapped to `describe-stroke'.

;;    2) stroke bindings are set internally through the Lisp function
;;       `define-stroke', similar to the `define-key' function.  some
;;       examples for a 3x3 stroke grid would be

;;       (define-stroke c-mode-stroke-map
;;                      '((0 . 0) (1 . 1) (2 . 2))
;;                      'kill-region)
;;       (define-stroke strokes-global-map
;;                      '((0 . 0) (0 . 1) (0 . 2) (1 . 2) (2 . 2))
;;                      'list-buffers)

;;       however, if you would probably just have the user enter in the
;;       stroke interactively and then set the stroke to whatever he/she
;;       entered. The Lisp function to interactively read a stroke is
;;       `strokes-read-stroke'.  This is especially helpful when you're
;;       on a fast computer that can handle a 9x9 stroke grid.

;;       NOTE: only global stroke bindings are currently implemented,
;;       however mode- and buffer-local stroke bindings may eventually
;;       be implemented in a future version.

;; The important variables to be aware of for this package are listed
;; below.  They can all be altered through the customizing package via

;; > M-x customize

;; and customizing the group named `strokes'.  You can also read
;; documentation on the variables there.

;; `strokes-minimum-match-score' (determines the threshold of error that
;; makes a stroke acceptable or unacceptable.  If your strokes arn't
;; matching, then you should raise this variable.

;; `strokes-grid-resolution' (determines the grid dimensions that you use
;; when defining/reading strokes.  The finer the grid your computer can
;; handle, the more you can do, but even a 3x3 grid is pretty cool.)
;; The default value (7) should be fine for most decent computers.
;; NOTE: This variable should not be set to a number less than 3.

;; `strokes-display-strokes-buffer' will allow you to hide the strokes
;; buffer when doing simple strokes.  This is a speedup for slow
;; computers as well as people who don't want to see their strokes.

;; If you find that your mouse is accelerating too fast, you can
;; execute the UNIX X command to slow it down.  A good possibility is

;; % xset m 5/4 8

;; which seems, heuristically, to work okay, without much disruption.

;; Whenever you load in the strokes package, you will be able to save
;; what you've done upon exiting Emacs.  You can also do

;; > M-x save-strokes

;; and it will save your strokes in ~/.strokes, or you may wish to change
;; this by setting the variable `strokes-file'.

;; Note that internally, all of the routines that are part of this
;; package are able to deal with complex strokes, as they are a superset
;; of simple strokes.  However, the default of this package will map
;; mouse button2 to the command `strokes-do-stroke', and NOT
;; `strokes-do-complex-stroke'.  If you wish to use complex strokes, you
;; will have to override this key mapping.  Complex strokes are terminated
;; with mouse button3.  The strokes package will not interfere with
;; `mouse-yank', but you may want to examine how this is done (see the
;; variable `strokes-click-command')

;; To get strokes to work as part of your your setup, then you'll have
;; put the strokes package in your load-path (preferably byte-compiled)
;; and then add the following to your .emacs file (or wherever
;; you put Emacs-specific startup preferences):

;;(and (fboundp 'device-on-window-system-p)
;;     (device-on-window-system-p)
;;     (require 'strokes))

;; Once loaded, you can start stroking.  You can also toggle between
;; strokes mode by simple typing

;; > M-x strokes-mode

;; I am now in the process of porting this package to Emacs.  I also hope
;; that, with the help of others, this package will be useful in entering
;; in pictographic-like language text using the mouse (i.e. Korean).
;; Japanese and Chinese are a bit trickier, but I'm sure that with help
;; it can be done.  The next version will allow the user to enter strokes
;; which "remove the pencil from the paper" so to speak, so one character
;; can have multiple strokes.

;; You can read more about strokes at:

;; http://www.mit.edu/people/cadet/strokes-help.html

;; If you're interested in using strokes for writing English into Emacs
;; using strokes, then you'll want to read about it on the web page above
;; or just download from http://www.mit.edu/people/cadet/strokes-abc.el,
;; which is nothing but a file with some helper commands for inserting
;; alphanumerics and punctuation.

;; Great thanks to Rob Ristroph for his generosity in letting me use his
;; PC to develop this, Jason Johnson for his help in algorithms, Euna
;; Kim for her help in Korean, and massive thanks to the helpful guys
;; on the help instance on athena (zeno, jered, amu, gsstark, ghudson, etc)
;; Special thanks to Steve Baur and Hrvoje Niksic for all their help.
;; And even more thanks to Dave Gillespie for all the elisp help--he
;; is responsible for helping me use the cl macros at (near) max speed.

;; Tasks: (what I'm getting ready for future version)...
;; 2) use 'strokes-read-complex-stroke for korean, etc.
;; 4) buffer-local 'strokes-local-map, and mode-stroke-maps would be nice
;; 5) 'list-strokes (kinda important).  What do people want?
;;    How about an optional docstring for each stroke so that a person
;;    can examine the strokes-file and actually make sense of it?
;;    (e.g. "This stroke is a pentagram")
;; 6) add some hooks, like `strokes-read-stroke-hook'
;; 7) See what people think of the factory settings.  Should I change
;;    them?  They're all pretty arbitrary in a way.  I guess they
;;    should be minimal, but computers are getting lots faster, and
;;    if I choose the defaults too conservatively, then strokes will
;;    surely dissapoint some people on decent machines (until they
;;    figure out M-x customize).  I need feedback.
;; Other: I always have the most beta version of strokes, so if you
;;        want it just let me know.

;;; Code:

;;; Requirements and provisions...

(autoload 'reporter-submit-bug-report "reporter")
(autoload 'mail-position-on-field "sendmail")
(eval-and-compile
  (mapcar 'require '(pp reporter advice custom cl))
  (mapcar 'load '("cl-macs" "cl-seq" "levents")))

;;; Constants...

(defconst strokes-version "0.0-beta")

(defconst strokes-bug-address "cadet@mit.edu")

(defconst strokes-lift 'strokes-lift
  "Symbol representing a stroke lift event for complex strokes.
Complex strokes are those which contain two or more simple strokes.
This will be useful for when Emacs understands Chinese.")

;;; user variables...

;; suggested Custom hack, so strokes is compatible with emacs19...

(eval-and-compile
  (if (fboundp 'defgroup) nil 
    (defmacro defgroup (&rest forms) nil)  
    (defmacro defcustom (name init doc &rest forms)  
      (list 'defvar name init doc))))

(defgroup strokes nil
  "Control Emacs through mouse strokes"
  :group 'mouse)

(defcustom strokes-modeline-string " Strokes"
  "*Modeline identification when strokes are on \(default is \" Strokes\"\)."
  :type 'string
  :group 'strokes)

(defcustom strokes-character ?@
  "*Character used when drawing strokes in the strokes buffer.
\(The default is lower-case `@', which works okay\)."
  :type 'character
  :group 'strokes)

(defcustom strokes-minimum-match-score 1000
  "*Minimum score for a stroke to be considered a possible match.
Requiring a perfect match would set this variable to 0.
The default value is 1000, but it's mostly dependent on how precisely
you manage to replicate your user-defined strokes.  It also depends on
the value of `strokes-grid-resolution', since a higher grid resolution
will correspond to more sample points, and thus more distance
measurements.  Usually, this is not a problem since you first set
`strokes-grid-resolution' based on what your computer seems to be able
to handle (though the defaults are usually more than sufficent), and
then you can set `strokes-minimum-match-score' to something that works
for you.  The only purpose of this variable is to insure that if you
do a bogus stroke that really doesn't match any of the predefined
ones, then strokes should NOT pick the one that came closest."
  :type 'integer
  :group 'strokes)

(defcustom strokes-grid-resolution 9
  "*Integer defining dimensions of the stroke grid.
The grid is a square grid, where STROKES-GRID-RESOLUTION defaults to
`9', making a 9x9 grid whose coordinates go from (0 . 0) on the top
left to ((STROKES-GRID-RESOLUTION - 1) . (STROKES-GRID-RESOLUTION - 1))
on the bottom right.  The greater the resolution, the more intricate
your strokes can be.
NOTE: This variable should be odd and MUST NOT be less than 3 and need
      not be greater than 33, which is the resolution of the pixmaps.
WARNING: Changing the value of this variable will gravely affect the
         strokes you have already programmed in.  You should try to
         figure out what it should be based on your needs and on how
         quick the particular platform(s) you're operating on, and
         only then start programming in your custom strokes."
  :type 'integer
  :group 'strokes)

(defcustom strokes-file (convert-standard-filename "~/.strokes")
  "*File containing saved strokes for stroke-mode (default is ~/.strokes)."
  :type 'file
  :group 'strokes)

(defcustom strokes-buffer-name " *strokes*"
  "The buffer that the strokes take place in (default is ` *strokes*')."
  :type 'string
  :group 'strokes)

(defcustom strokes-use-strokes-buffer t
  "*If non-nil, the strokes buffer is used and strokes are displayed.
If nil, strokes will be read the same, however the user will not be
able to see the strokes.  This be helpful for people who don't like
the delay in switching to the strokes buffer."
  :type 'boolean
  :group 'strokes)

(defcustom strokes-click-command 'mouse-yank-at-click
  "*Command to execute when stroke is actually a `click' event.
This is set to `mouse-yank-at-click' by default."
  :type 'function
  :group 'strokes)

;;; internal variables...

;;;###autoload
(defvar strokes-mode nil
  "Non-nil when `strokes' is globally enabled")

(defvar strokes-window-configuration nil
  "The special window configuration used when entering strokes.
This is set properly in the function `strokes-update-window-configuration'.")

(defvar strokes-last-stroke nil
  "Last stroke entered by the user.
Its value gets set every time the function
`strokes-fill-stroke' gets called,
since that is the best time to set the variable")

(defvar strokes-global-map '()
  "Association list of strokes and their definitions.
Each entry is (STROKE . COMMAND) where STROKE is itself a list of
coordinates (X . Y) where X and Y are lists of positions on the
normalized stroke grid, with the top left at (0 . 0).  COMMAND is the
corresponding interactive function")

(defvar strokes-load-hook nil
  "Function or functions to be called when `strokes' is loaded.")

;;; Macros...

(defsubst strokes-click-p (stroke)
  "Non-nil if STROKE is really click."
  (< (length stroke) 2))

;;; old, but worked pretty good (just in case)...
;;(defmacro strokes-define-stroke (stroke-map stroke def)
;;  "Add STROKE to STROKE-MAP alist with given command DEF"
;;  (list 'if (list '< (list 'length stroke) 2)
;;      (list 'error
;;            "That's a click, not a stroke.  See `strokes-click-command'")
;;      (list 'setq stroke-map (list 'cons (list 'cons stroke def)
;;                                   (list 'remassoc stroke stroke-map)))))

(defsubst strokes-remassoc (key list)
  (remove-if
   (lambda (element)
     (equal key (car element)))
   list))

(defmacro strokes-define-stroke (stroke-map stroke def)
  "Add STROKE to STROKE-MAP alist with given command DEF."
  `(if (strokes-click-p ,stroke)
       (error "That's a click, not a stroke; see `strokes-click-command'")
     (setq ,stroke-map (cons (cons ,stroke ,def)
                             (strokes-remassoc ,stroke ,stroke-map)))))

(defalias 'define-stroke 'strokes-define-stroke)

(defsubst strokes-square (x)
  "Returns the square of the number X"
  (* x x))

(defsubst strokes-distance-squared (p1 p2)
  "Gets the distance (squared) between to points P1 and P2.
P1 and P2 are cons cells in the form (X . Y)."
  (let ((x1 (car p1))
        (y1 (cdr p1))
        (x2 (car p2))
        (y2 (cdr p2)))
    (+ (strokes-square (- x2 x1))
       (strokes-square (- y2 y1)))))

;;; Advice for various functions...

;; I'd originally wanted to write a macro that would just take in the
;; generic functions which use mouse button2 in various modes.  Most of
;; them are identical in form: they take an event as the single argument
;; and then do their thing.  I tried writing a macro that looked
;; something like this, but failed.  Advice just ain't that easy.  The
;; one that bugged me the most was `Manual-follow-xref', because that had
;; &rest arguments, and I didn't know how to work around it in defadvice.
;; However, I was able to fix up most of the important modes (i.e. the
;; ones I use all the time).  One `bug' in the program that I just can't
;; seem to figure out is why I can only advise other button2 functions
;; successfully when the variable `strokes-use-strokes-buffer' is nil.  I
;; did all the save-excursion/save-window-excursion stuff SPECIFICALLY so
;; that using the strokes buffer or not would absolutely not affect any
;; other part of the program.  If someone can figure out how to make the
;; following advices work w/ regardless of that variable
;; `strokes-use-strokes-buffer', then that would be a great victory.  If
;; someone out there would be kind enough to make the commented code
;; below work, I'd be grateful.  By the way, I put the `protect' keywords
;; there to insure that if a stroke went bad, then
;; `strokes-click-command' would be set back.  If this isn't necessary,
;; then feel free to let me know.

;; For what follows, I really wanted something that would work like this:

;;(strokes-fix-button2 'vm-mouse-button-2)

;; Or even better, I could have simply done something like:

;;(mapcar 'strokes-fix-button2
;;        '(vm-mouse-button-2
;;          rmail-summary-mouse-goto-msg
;;          <rest of them>))

;;; With help from Hans (author of advice.el)...
(defmacro strokes-fix-button2-command (command)
  "Fix COMMAND so that it can also work with strokes.
COMMAND must take one event argument.
Example of how one might fix up a command that's bound to button2
and which is an interactive funcion of one event argument:

\(strokes-fix-button2-command 'rmail-summary-mouse-goto-msg)"
  (let ((command (eval command)))
    `(progn
       (defadvice ,command (around strokes-fix-button2 compile preactivate)
         ,(format "Fix %s to work with strokes." command)
         (if strokes-use-strokes-buffer
             ;; then strokes is no good and we'll have to use the original
             ad-do-it
           ;; otherwise, we can make strokes work too...
           (let ((strokes-click-command
                  ',(intern (format "ad-Orig-%s" command))))
             (strokes-do-stroke (ad-get-arg 0))))))))

(strokes-fix-button2-command 'vm-mouse-button-2)
(strokes-fix-button2-command 'rmail-summary-mouse-goto-msg)
(strokes-fix-button2-command 'Buffer-menu-mouse-select)
(strokes-fix-button2-command 'w3-widget-button-click)
(strokes-fix-button2-command 'widget-image-button-press)
(strokes-fix-button2-command 'Info-follow-clicked-node)
(strokes-fix-button2-command 'compile-mouse-goto-error)
(strokes-fix-button2-command 'gdbsrc-select-or-yank)
(strokes-fix-button2-command 'hypropos-mouse-get-doc)
(strokes-fix-button2-command 'gnus-mouse-pick-group)
(strokes-fix-button2-command 'gnus-mouse-pick-article)
(strokes-fix-button2-command 'gnus-article-push-button)
(strokes-fix-button2-command 'dired-mouse-find-file)
(strokes-fix-button2-command 'url-dired-find-file-mouse)
(strokes-fix-button2-command 'dired-u-r-mouse-toggle)
(strokes-fix-button2-command 'dired-u-w-mouse-toggle)
(strokes-fix-button2-command 'dired-u-x-mouse-toggle)
(strokes-fix-button2-command 'dired-g-r-mouse-toggle)
(strokes-fix-button2-command 'dired-g-w-mouse-toggle)
(strokes-fix-button2-command 'dired-g-x-mouse-toggle)
(strokes-fix-button2-command 'dired-o-r-mouse-toggle)
(strokes-fix-button2-command 'dired-o-w-mouse-toggle)
(strokes-fix-button2-command 'isearch-yank-x-selection)
(strokes-fix-button2-command 'occur-mode-mouse-goto)
(strokes-fix-button2-command 'cvs-mouse-find-file)

;;; I can fix the customize widget button click, but then
;;; people will get confused when they try to customize
;;; strokes with the mouse and customize tells them that
;;; `strokes-click-command' is mapped to `ad-Orig-widget-button-click'
;;(strokes-fix-button2-command 'widget-button-click)

;;; without the advice, each advised function would look like...
;;(defadvice vm-mouse-button-2 (around vm-strokes activate protect)
;;  "Allow strokes to work in VM."
;;  (if strokes-use-strokes-buffer
;;      ;; then strokes is no good and we'll have to use the original
;;      ad-do-it
;;    ;; otherwise, we can make strokes work too...
;;    (let ((strokes-click-command 'ad-Orig-vm-mouse-button-2))
;;      (strokes-do-stroke (ad-get-arg 0)))))

;;; Functions...

(defsubst strokes-mouse-event-p (event)
  (or (motion-event-p event)
      (button-press-event-p event)
      (button-release-event-p event)))

(defun strokes-event-closest-point-1 (window &optional line)
  "Return position of start of line LINE in WINDOW.
If LINE is nil, return the last position visible in WINDOW."
  (let* ((total (- (window-height window)
                   (if (window-minibuffer-p window)
                       0 1)))
         (distance (or line total)))
    (save-excursion
      (goto-char (window-start window))
      (if (= (vertical-motion distance) distance)
          (if (not line)
              (forward-char -1)))
      (point))))

(defun strokes-event-closest-point (event &optional start-window)
  "Return the nearest position to where EVENT ended its motion.
This is computed for the window where EVENT's motion started,
or for window WINDOW if that is specified."
  (or start-window (setq start-window (posn-window (event-start event))))
  (if (eq start-window (posn-window (event-end event)))
      (if (eq (event-point event) 'vertical-line)
          (strokes-event-closest-point-1 start-window
                                         (cdr (posn-col-row (event-end event))))
        (if (eq (event-point event) 'mode-line)
            (strokes-event-closest-point-1 start-window)
          (event-point event)))
    ;; EVENT ended in some other window.
    (let* ((end-w (posn-window (event-end event)))
           (end-w-top)
           (w-top (nth 1 (window-edges start-window))))
      (setq end-w-top
            (if (windowp end-w)
                (nth 1 (window-edges end-w))
              (/ (cdr (posn-x-y (event-end event)))
                 (frame-char-height end-w))))
      (if (>= end-w-top w-top)
          (strokes-event-closest-point-1 start-window)
        (window-start start-window)))))

(defun strokes-lift-p (object)
  "Return non-nil if object is a stroke-lift."
  (eq object strokes-lift))

(defun strokes-unset-last-stroke ()
  "Undo the last stroke definition."
  (interactive)
  (let ((command (cdar strokes-global-map)))
    (if (y-or-n-p
         (format "really delete last stroke definition, defined to `%s'? "
                 command))
        (progn
          (setq strokes-global-map (cdr strokes-global-map))
          (message "That stroke has been deleted"))
      (message "Nothing done"))))

;;;###autoload
(defun strokes-global-set-stroke (stroke command)
  "Interactively give STROKE the global binding as COMMAND.
Operated just like `global-set-key', except for strokes.
COMMAND is a symbol naming an interactively-callable function.  STROKE
is a list of sampled positions on the stroke grid as described in the
documentation for the `strokes-define-stroke' function."
  (interactive
   (list
    (and (or strokes-mode (strokes-mode t))
         (strokes-read-complex-stroke
          "Define a new stroke.  Draw with button1 (or 2).  End with button3..."))
    (read-command "command to map stroke to: ")))
  (strokes-define-stroke strokes-global-map stroke command))

;;;###autoload
(defalias 'global-set-stroke 'strokes-global-set-stroke)

;;(defun global-unset-stroke (stroke); FINISH THIS DEFUN!
;;  "delete all strokes matching STROKE from `strokes-global-map',
;; letting the user input
;; the stroke with the mouse"
;;  (interactive
;;   (list
;;    (strokes-read-stroke "Enter the stroke you want to delete...")))
;;  (strokes-define-stroke 'strokes-global-map stroke command))

(defun strokes-get-grid-position (stroke-extent position &optional grid-resolution)
  "Map POSITION to a new grid position based on its STROKE-EXTENT and GRID-RESOLUTION.
STROKE-EXTENT as a list \(\(XMIN . YMIN\) \(XMAX . YMAX\)\).
If POSITION is a `strokes-lift', then it is itself returned.
Optional GRID-RESOLUTION may be used in place of STROKES-GRID-RESOLUTION.
The grid is a square whose dimesion is [0,GRID-RESOLUTION)."
  (cond ((consp position)               ; actual pixel location
         (let ((grid-resolution (or grid-resolution strokes-grid-resolution))
               (x (car position))
               (y (cdr position))
               (xmin (caar stroke-extent))
               (ymin (cdar stroke-extent))
               ;; the `1+' is there to insure that the
               ;; formula evaluates correctly at the boundaries
               (xmax (1+ (caadr stroke-extent)))
               (ymax (1+ (cdadr stroke-extent))))
           (cons (floor (* grid-resolution
                           (/ (float (- x xmin))
                              (- xmax xmin))))
                 (floor (* grid-resolution
                           (/ (float (- y ymin))
                              (- ymax ymin)))))))
        ((strokes-lift-p position)      ; stroke lift
         strokes-lift)))

;;(defun strokes-get-grid-position (stroke-extent pix-pos)
;;  "Return the stroke-grid position for PIX-POS given the total STROKE-EXTENT.
;;STROKE-EXTENT as a list \(\(xmin . ymin\) \(xmax . ymax\)\) and a particular
;;pixel position or `strokes-lift', find the corresponding grid position
;;\(based on `strokes-grid-resolution'\) for the PIX-POS."
;;  (cond ((consp pix-pos)              ; actual pixel location
;;       (let ((x (car pix-pos))
;;             (y (cdr pix-pos))
;;             (xmin (caar stroke-extent))
;;             (ymin (cdar stroke-extent))
;;             ;; the `1+' is there to insure that the
;;             ;; formula evaluates correctly at the boundaries
;;             (xmax (1+ (caadr stroke-extent)))
;;             (ymax (1+ (cdadr stroke-extent))))
;;         (cons (floor (* strokes-grid-resolution
;;                         (/ (float (- x xmin))
;;                            (- xmax xmin))))
;;               (floor (* strokes-grid-resolution
;;                         (/ (float (- y ymin))
;;                            (- ymax ymin)))))))
;;      ((strokes-lift-p pix-pos)       ; stroke lift
;;       strokes-lift)))

(defun strokes-get-stroke-extent (pixel-positions)
  "From a list of absolute PIXEL-POSITIONS, returns absolute spatial extent.
The return value is a list ((XMIN . YMIN) (XMAX . YMAX))."
  (if pixel-positions
      (let ((xmin (caar pixel-positions))
            (xmax (caar pixel-positions))
            (ymin (cdar pixel-positions))
            (ymax (cdar pixel-positions))
            (rest (cdr pixel-positions)))
        (while rest
          (if (consp (car rest))
              (let ((x (caar rest))
                    (y (cdar rest)))
                (if (< x xmin)
                    (setq xmin x))
                (if (> x xmax)
                    (setq xmax x))
                (if (< y ymin)
                    (setq ymin y))
                (if (> y ymax)
                    (setq ymax y))))
          (setq rest (cdr rest)))
        (let ((delta-x (- xmax xmin))
              (delta-y (- ymax ymin)))
          (if (> delta-x delta-y)
              (setq ymin (- ymin
                            (/ (- delta-x delta-y)
                               2))
                    ymax (+ ymax
                            (/ (- delta-x delta-y)
                               2)))
            (setq xmin (- xmin
                          (/ (- delta-y delta-x)
                             2))
                  xmax (+ xmax
                          (/ (- delta-y delta-x)
                             2))))
          (list (cons xmin ymin)
                (cons xmax ymax))))
    nil))

(defun strokes-eliminate-consecutive-redundancies (entries)
  "Returns a list with no consecutive redundant entries."
  ;; defun a grande vitesse grace a Dave G.
  (loop for element on entries
        if (not (equal (car element) (cadr element)))
        collect (car element)))
;;  (loop for element on entries
;;        nconc (if (not (equal (car el) (cadr el)))
;;                  (list (car el)))))
;; yet another (orig) way of doing it...
;;  (if entries
;;      (let* ((current (car entries))
;;           (rest (cdr entries))
;;           (non-redundant-list (list current))
;;           (next nil))
;;      (while rest
;;        (setq next (car rest))
;;        (if (equal current next)
;;            (setq rest (cdr rest))
;;          (setq non-redundant-list (cons next non-redundant-list)
;;                current next
;;                rest (cdr rest))))
;;      (nreverse non-redundant-list))
;;    nil))

(defun strokes-renormalize-to-grid (positions &optional grid-resolution)
  "Map POSITIONS to a new grid whose dimensions are based on GRID-RESOLUTION.
POSITIONS is a list of positions and stroke-lifts.
Optional GRID-RESOLUTION may be used in place of STROKES-GRID-RESOLUTION.
The grid is a square whose dimesion is [0,GRID-RESOLUTION)."
  (or grid-resolution (setq grid-resolution strokes-grid-resolution))
  (let ((stroke-extent (strokes-get-stroke-extent positions)))
    (mapcar (function
             (lambda (pos)
               (strokes-get-grid-position stroke-extent pos grid-resolution)))
            positions)))

;;(defun strokes-normalize-pixels-to-grid (pixel-positions)
;;  "Map PIXEL-POSITIONS to the stroke grid.
;;PIXEL-POSITIONS is a list of pixel-positions and stroke-lifts.  The
;;normalized stroke grid is defined by the variable STROKES-GRID-RESOLUTION"
;;  (let ((stroke-extent (strokes-get-stroke-extent pixel-positions)))
;;    (mapcar (function
;;           (lambda (pix-pos)
;;             (strokes-get-grid-position stroke-extent pix-pos)))
;;          pixel-positions)))

(defun strokes-fill-stroke (unfilled-stroke &optional force)
  "Fill in missing grid locations in the list of UNFILLED-STROKE.
If FORCE is non-nil, then fill the stroke even if it's `stroke-click'.
NOTE: This is where the global variable `strokes-last-stroke' is set."
  (setq strokes-last-stroke             ; this is global
        (if (and (strokes-click-p unfilled-stroke)
                 (not force))
            unfilled-stroke
          (loop for grid-locs on unfilled-stroke
                nconc (let* ((current (car grid-locs))
                             (current-is-a-point-p (consp current))
                             (next (cadr grid-locs))
                             (next-is-a-point-p (consp next))
                             (both-are-points-p (and current-is-a-point-p
                                                     next-is-a-point-p))
                             (x1 (and current-is-a-point-p
                                      (car current)))
                             (y1 (and current-is-a-point-p
                                      (cdr current)))
                             (x2 (and next-is-a-point-p
                                      (car next)))
                             (y2 (and next-is-a-point-p
                                      (cdr next)))
                             (delta-x (and both-are-points-p
                                           (- x2 x1)))
                             (delta-y (and both-are-points-p
                                           (- y2 y1)))
                             (slope (and both-are-points-p
                                         (if (zerop delta-x)
                                             nil ; undefined vertical slope
                                           (/ (float delta-y)
                                              delta-x)))))
                        (cond ((not both-are-points-p)
                               (list current))
                              ((null slope) ; undefinded vertical slope
                               (if (>= delta-y 0)
                                   (loop for y from y1 below y2
                                         collect (cons x1 y))
                                 (loop for y from y1 above y2
                                       collect (cons x1 y))))
                              ((zerop slope) ; (= y1 y2)
                               (if (>= delta-x 0)
                                   (loop for x from x1 below x2
                                         collect (cons x y1))
                                 (loop for x from x1 above x2
                                       collect (cons x y1))))
                              ((>= (abs delta-x) (abs delta-y))
                               (if (> delta-x 0)
                                   (loop for x from x1 below x2
                                         collect (cons x
                                                       (+ y1
                                                          (round (* slope
                                                                    (- x x1))))))
                                 (loop for x from x1 above x2
                                       collect (cons x
                                                     (+ y1
                                                        (round (* slope
                                                                  (- x x1))))))))
                              (t        ; (< (abs delta-x) (abs delta-y))
                               (if (> delta-y 0)
                                   (loop for y from y1 below y2
                                         collect (cons (+ x1
                                                          (round (/ (- y y1)
                                                                    slope)))
                                                       y))
                                 (loop for y from y1 above y2
                                       collect (cons (+ x1
                                                        (round (/ (- y y1)
                                                                  slope)))
                                                     y))))))))))

(defun strokes-rate-stroke (stroke1 stroke2)
  "Rates STROKE1 with STROKE2 and returns a score based on a distance metric.
Note: the rating is an error rating, and therefore, a return of 0
represents a perfect match.  Also note that the order of stroke
arguments is order-independent for the algorithm used here."
  (if (and stroke1 stroke2)
      (let ((rest1 (cdr stroke1))
            (rest2 (cdr stroke2))
            (err (strokes-distance-squared (car stroke1)
                                           (car stroke2))))
        (while (and rest1 rest2)
          (while (and (consp (car rest1))
                      (consp (car rest2)))
            (setq err (+ err
                         (strokes-distance-squared (car rest1)
                                                   (car rest2)))
                  stroke1 rest1
                  stroke2 rest2
                  rest1 (cdr stroke1)
                  rest2 (cdr stroke2)))
          (cond ((and (strokes-lift-p (car rest1))
                      (strokes-lift-p (car rest2)))
                 (setq rest1 (cdr rest1)
                       rest2 (cdr rest2)))
                ((strokes-lift-p (car rest2))
                 (while (consp (car rest1))
                   (setq err (+ err
                                (strokes-distance-squared (car rest1)
                                                          (car stroke2)))
                         rest1 (cdr rest1))))
                ((strokes-lift-p (car rest1))
                 (while (consp (car rest2))
                   (setq err (+ err
                                (strokes-distance-squared (car stroke1)
                                                          (car rest2)))
                         rest2 (cdr rest2))))))
        (if (null rest2)
            (while (consp (car rest1))
              (setq err (+ err
                           (strokes-distance-squared (car rest1)
                                                     (car stroke2)))
                    rest1 (cdr rest1))))
        (if (null rest1)
            (while (consp (car rest2))
              (setq err (+ err
                           (strokes-distance-squared (car stroke1)
                                                     (car rest2)))
                    rest2 (cdr rest2))))
        (if (or (strokes-lift-p (car rest1))
                (strokes-lift-p (car rest2)))
            (setq err nil)
          err))
    nil))

(defun strokes-match-stroke (stroke stroke-map)
  "Finds the best matching command of STROKE in STROKE-MAP.
Returns the corresponding match as (COMMAND . SCORE)."
  (if (and stroke stroke-map)
      (let ((score (strokes-rate-stroke stroke (caar stroke-map)))
            (command (cdar stroke-map))
            (map (cdr stroke-map)))
        (while map
          (let ((newscore (strokes-rate-stroke stroke (caar map))))
            (if (or (and newscore score (< newscore score))
                    (and newscore (null score)))
                (setq score newscore
                      command (cdar map)))
            (setq map (cdr map))))
        (if score
            (cons command score)
          nil))
    nil))

;;;###autoload
(defun strokes-read-stroke (&optional prompt event)
  "Read a simple stroke (interactively) and return the stroke.
Optional PROMPT in minibuffer displays before and during stroke reading.
This function will display the stroke interactively as it is being
entered in the strokes buffer if the variable
`strokes-use-strokes-buffer' is non-nil.
Optional EVENT is acceptable as the starting event of the stroke"
  (save-excursion
    (let ((pix-locs nil)
          (grid-locs nil)
          (safe-to-draw-p nil))
      (if strokes-use-strokes-buffer
          ;; switch to the strokes buffer and
          ;; display the stroke as it's being read
          (save-window-excursion
            (set-window-configuration strokes-window-configuration)
            (when prompt
              (message prompt)
              (setq event (read-event))
              (or (button-press-event-p event)
                  (error "You must draw with the mouse")))
            (unwind-protect
                (track-mouse
                  (or event (setq event (read-event)
                                  safe-to-draw-p t))
                  (while (not (button-release-event-p event))
                    (if (strokes-mouse-event-p event)
                        (let ((point (strokes-event-closest-point event)))
                          (if (and point safe-to-draw-p)
                              ;; we can draw that point
                              (progn
                                (goto-char point)
                                (subst-char-in-region point (1+ point) ?\  strokes-character))
                            ;; otherwise, we can start drawing the next time...
                            (setq safe-to-draw-p t))
                          (push (cons (event-x-pixel event)
                                      (event-y-pixel event))
                                pix-locs)))
                    (setq event (read-event)))))
            ;; protected
            ;; clean up strokes buffer and then bury it.
            (when (equal (buffer-name) strokes-buffer-name)
              (subst-char-in-region (point-min) (point-max) strokes-character ?\ )
              (goto-char (point-min))
              (bury-buffer))))
      ;; Otherwise, don't use strokes buffer and read stroke silently
      (when prompt
        (message prompt)
        (setq event (read-event))
        (or (button-press-event-p event)
            (error "You must draw with the mouse")))
      (track-mouse
        (or event (setq event (read-event)))
        (while (not (button-release-event-p event))
          (if (strokes-mouse-event-p event)
              (push (cons (event-x-pixel event)
                          (event-y-pixel event))
                    pix-locs))
          (setq event (read-event))))
      (setq grid-locs (strokes-renormalize-to-grid (nreverse pix-locs)))
      (strokes-fill-stroke (strokes-eliminate-consecutive-redundancies grid-locs)))))

;;;###autoload
(defun strokes-read-complex-stroke (&optional prompt event)
  "Read a complex stroke (interactively) and return the stroke.
Optional PROMPT in minibuffer displays before and during stroke reading.
Note that a complex stroke allows the user to pen-up and pen-down.  This
is implemented by allowing the user to paint with button1 or button2 and
then complete the stroke with button3.
Optional EVENT is acceptable as the starting event of the stroke"
  (save-excursion
    (save-window-excursion
      (set-window-configuration strokes-window-configuration)
      (let ((pix-locs nil)
            (grid-locs nil))
        (if prompt
            (while (not (button-press-event-p event))
              (message prompt)
              (setq event (read-event))))
        (unwind-protect
            (track-mouse
              (or event (setq event (read-event)))
              (while (not (and (button-press-event-p event)
                               (eq (event-button event) 3)))
                (while (not (button-release-event-p event))
                  (if (strokes-mouse-event-p event)
                      (let ((point (strokes-event-closest-point event)))
                        (when point
                          (goto-char point)
                          (subst-char-in-region point (1+ point) ?\ strokes-character))
                        (push (cons (event-x-pixel event)
                                    (event-y-pixel event))
                              pix-locs)))
                  (setq event (read-event)))
                (push strokes-lift pix-locs)
                (while (not (button-press-event-p event))
                  (setq event (read-event))))
              ;; ### KLUDGE! ### sit and wait
              ;; for some useless event to
              ;; happen to fix the minibuffer bug.
              (while (not (button-release-event-p (read-event))))
              (setq pix-locs (nreverse (cdr pix-locs))
                    grid-locs (strokes-renormalize-to-grid pix-locs))
              (strokes-fill-stroke
               (strokes-eliminate-consecutive-redundancies grid-locs)))
          ;; protected
          (when (equal (buffer-name) strokes-buffer-name)
            (subst-char-in-region (point-min) (point-max) strokes-character ?\ )
            (goto-char (point-min))
            (bury-buffer)))))))

(defun strokes-execute-stroke (stroke)
  "Given STROKE, execute the command which corresponds to it.
The command will be executed provided one exists for that stroke,
based on the variable `strokes-minimum-match-score'.
If no stroke matches, nothing is done and return value is nil."
  (let* ((match (strokes-match-stroke stroke strokes-global-map))
         (command (car match))
         (score (cdr match)))
    (cond ((strokes-click-p stroke)
           ;; This is the case of a `click' type event
           (command-execute strokes-click-command))
          ((and match (<= score strokes-minimum-match-score))
           (message "%s" command)
           (command-execute command))
          ((null strokes-global-map)
           (if (file-exists-p strokes-file)
               (and (y-or-n-p
                     (format "No strokes loaded.  Load `%s'? "
                             strokes-file))
                    (strokes-load-user-strokes))
             (error "No strokes defined; use `global-set-stroke'")))
          (t
           (error
            "No stroke matches; see variable `strokes-minimum-match-score'")
           nil))))

;;;###autoload
(defun strokes-do-stroke (event)
  "Read a simple stroke from the user and then exectute its comand.
This must be bound to a mouse event."
  (interactive "e")
  (or strokes-mode (strokes-mode t))
  (strokes-execute-stroke (strokes-read-stroke nil event)))

;;;###autoload
(defun strokes-do-complex-stroke (event)
  "Read a complex stroke from the user and then exectute its command.
This must be bound to a mouse event."
  (interactive "e")
  (or strokes-mode (strokes-mode t))
  (strokes-execute-stroke (strokes-read-complex-stroke nil event)))

;;;###autoload
(defun strokes-describe-stroke (stroke)
  "Displays the command which STROKE maps to, reading STROKE interactively."
  (interactive
   (list
    (strokes-read-complex-stroke
     "Enter stroke to describe; end with button3...")))
  (let* ((match (strokes-match-stroke stroke strokes-global-map))
         (command (or (and (strokes-click-p stroke)
                           strokes-click-command)
                      (car match)))
         (score (cdr match)))
    (if (or (and match
                 (<= score strokes-minimum-match-score))
            (and (strokes-click-p stroke)
                 strokes-click-command))
        (message "That stroke maps to `%s'" command)
      (message "That stroke is undefined"))
    (sleep-for 1)))                     ; helpful for recursive edits

;;;###autoload
(defalias 'describe-stroke 'strokes-describe-stroke)

;;;###autoload
(defun strokes-help ()
  "Get instructional help on using the the `strokes' package."
  (interactive)
  (with-output-to-temp-buffer "*Help with Strokes*"
    (let ((helpdoc
           "This is help for the strokes package.

If you find something wrong with strokes, or feel that it can be
improved in some way, then please feel free to email me:

David Bakhash <cadet@mit.edu>

or just do

M-x strokes-report-bug

------------------------------------------------------------

** Strokes...

The strokes package allows you to define strokes, made with
the mouse or other pointer device, that Emacs can interpret as
corresponding to commands, and then executes the commands.  It does
character recognition, so you don't have to worry about getting it
right every time.

Strokes are easy to program and fun to use.  To start strokes going,
you'll want to put the following line in your .emacs file as mentioned
in the commentary to strokes.el.

This will load strokes when and only when you start Emacs on a window
system, with a mouse or other pointer device defined.

To toggle strokes-mode, you just do

> M-x strokes-mode

** Strokes for controling the behavior of Emacs...

When you're ready to start defining strokes, just use the command

> M-x global-set-stroke

You will see a ` *strokes*' buffer which is waiting for you to enter in
your stroke.  When you enter in the stroke, you draw with button1 or
button2, and then end with button3.  Next, you enter in the command
which will be executed when that stroke is invoked.  Simple as that.
For now, try to define a stroke to copy a region.  This is a popular
edit command, so type

> M-x global-set-stroke

Then, in the ` *strokes*' buffer, draw the letter `C' (for `copy'\)
and then, when it asks you to enter the command to map that to, type

> copy-region-as-kill

That's about as hard as it gets.
Remember: paint with button1 or button2 and then end with button3.

If ever you want to know what a certain strokes maps to, then do

> M-x describe-stroke

and you can enter in any arbitrary stroke.  Remember: The strokes
package lets you program in simple and complex, or multi-lift, strokes.
The only difference is how you *invoke* the two.  You will most likely
use simple strokes, as complex strokes were developed for
Chinese/Japanese/Korean.  So the middle mouse button, button2, will
invoke the command `strokes-do-stroke' in buffers where button2 doesn't
already have a meaning other than its original, which is `mouse-yank'.
But don't worry: `mouse-yank' will still work with strokes.  See the
variable `strokes-click-command'.

If ever you define a stroke which you don't like, then you can unset
it with the command

> M-x strokes-unset-last-stroke

Your strokes are stored as you enter them.  They get saved in a file
called ~/.strokes, along with other strokes configuration variables.
You can change this location by setting the variable `strokes-file'.
You will be prompted to save them when you exit Emacs, or you can save
them with

> M-x save-strokes

Your strokes get loaded automatically when you enable `strokes-mode'.
You can also load in your user-defined strokes with

> M-x load-user-strokes

** A few more important things...

o The command `strokes-do-stroke' is also invoked with M-button2, so that you
  can still enter a stroke in modes which use button2 for other things,
  such as cross-referencing.

o Strokes are a bit computer-dependent in that they depend somewhat on
  the speed of the computer you're working on.  This means that you
  may have to tweak some variables.  You can read about them in the
  commentary of `strokes.el'.  Better to just use apropos and read their
  docstrings.  All variables/functions start with `strokes'.  The one
  variable which many people wanted to see was
  `strokes-use-strokes-buffer' which allows the user to use strokes
  silently--without displaying the strokes.  All variables can be set
  by customizing the group named `strokes' via the customization package:

  > M-x customize"))
    (save-excursion
        (princ helpdoc)
        (set-buffer standard-output)
        (help-mode))
      (print-help-return-message))))

(defun strokes-report-bug ()
  "Submit a bug report for strokes."
  (interactive)
  (let ((reporter-prompt-for-summary-p t))
    (or (boundp 'reporter-version)
        (setq reporter-version
              "Your version of reporter is obsolete.  Please upgrade."))
    (reporter-submit-bug-report
     strokes-bug-address "Strokes"
     (cons
      'strokes-version
      (nconc
       (mapcar
        'intern
        (sort
         (let (completion-ignore-case)
           (all-completions "strokes-" obarray 'user-variable-p))
         'string-lessp))
       (list 'reporter-version)))
     (function
      (lambda ()
        (save-excursion
          (mail-position-on-field "subject")
          (beginning-of-line)
          (skip-chars-forward "^:\n")
          (if (looking-at ": Strokes;")
              (progn
                (goto-char (match-end 0))
                (delete-char -1)
                (insert " " strokes-version " bug:")))))))))

(defsubst strokes-fill-current-buffer-with-whitespace ()
  "Erase the contents of the current buffer and fill it with whitespace"
  (erase-buffer)
  (loop repeat (frame-height) do
        (insert-char ?\  (1- (frame-width)))
        (newline))
  (goto-char (point-min)))

(defun strokes-update-window-configuration ()
  "Insure that `strokes-window-configuration' is up-to-date."
  (interactive)
  (let ((current-window (selected-window)))
    (cond ((or (window-minibuffer-p current-window)
               (window-dedicated-p current-window))
           ;; don't try to update strokes window configuration
           ;; if window is dedicated or a minibuffer
           nil)
          ((or (interactive-p)
               (not (bufferp (get-buffer strokes-buffer-name)))
               (null strokes-window-configuration))
           ;; create `strokes-window-configuration' from scratch...
           (save-excursion
             (save-window-excursion
               (get-buffer-create strokes-buffer-name)
               (set-window-buffer current-window strokes-buffer-name)
               (delete-other-windows)
               (fundamental-mode)
               (auto-save-mode 0)
               (if (featurep 'font-lock)
                   (font-lock-mode 0))
               (abbrev-mode 0)
               (buffer-disable-undo (current-buffer))
               (setq truncate-lines nil)
               (strokes-fill-current-buffer-with-whitespace)
               (setq strokes-window-configuration (current-window-configuration))
               (bury-buffer))))
          (t                            ; `strokes buffer' still exists...
           ;; update the strokes-window-configuration for this specific frame...
           (save-excursion
             (save-window-excursion
               (set-window-buffer current-window strokes-buffer-name)
               (delete-other-windows)
               (strokes-fill-current-buffer-with-whitespace)
               (setq strokes-window-configuration (current-window-configuration))
               (bury-buffer)))))))

;;;###autoload
(defun strokes-load-user-strokes ()
  "Load user-defined strokes from file named by `strokes-file'."
  (interactive)
  (cond ((and (file-exists-p strokes-file)
              (file-readable-p strokes-file))
         (load-file strokes-file))
        ((interactive-p)
         (error "Trouble loading user-defined strokes; nothing done"))
        (t
         (message "No user-defined strokes, sorry"))))

;;;###autoload
(defalias 'load-user-strokes 'strokes-load-user-strokes)

(defun strokes-prompt-user-save-strokes ()
  "Save user-defined strokes to file named by `strokes-file'."
  (interactive)
  (save-excursion
    (let ((current strokes-global-map))
      (unwind-protect
          (progn
            (setq strokes-global-map nil)
            (strokes-load-user-strokes)
            (if (and (not (equal current strokes-global-map))
                     (or (interactive-p)
                         (yes-or-no-p "save your strokes? ")))
                (progn
                  (require 'pp)         ; pretty-print variables
                  (message "Saving strokes in %s..." strokes-file)
                  (get-buffer-create "*saved-strokes*")
                  (set-buffer "*saved-strokes*")
                  (erase-buffer)
                  (emacs-lisp-mode)
                  (goto-char (point-min))
                  (insert-string
                   ";;   -*- Syntax: Emacs-Lisp; Mode: emacs-lisp -*-\n")
                  (insert-string (format ";;; saved strokes for %s, as of %s\n\n"
                                         (user-full-name)
                                         (format-time-string "%B %e, %Y" nil)))
                  (message "Saving strokes in %s..." strokes-file)
                  (insert-string (format "(setq strokes-global-map '%s)"
                                         (pp current)))
                  (message "Saving strokes in %s..." strokes-file)
                  (indent-region (point-min) (point-max) nil)
                  (write-region (point-min)
                                (point-max)
                                strokes-file))
              (message "(no changes need to be saved)")))
        ;; protected
        (if (get-buffer "*saved-strokes*")
            (kill-buffer (get-buffer "*saved-strokes*")))
        (setq strokes-global-map current)))))

(defalias 'save-strokes 'strokes-prompt-user-save-strokes)

(defun strokes-toggle-strokes-buffer (&optional arg)
  "Toggle the use of the strokes buffer.
In other words, toggle the variabe `strokes-use-strokes-buffer'.
With ARG, use strokes buffer if and only if ARG is positive or true.
Returns value of `strokes-use-strokes-buffer'."
  (interactive "P")
  (setq strokes-use-strokes-buffer
        (if arg (> (prefix-numeric-value arg) 0)
          (not strokes-use-strokes-buffer))))

;;;###autoload
(defun strokes-mode (&optional arg)
  "Toggle strokes being enabled.
With ARG, turn strokes on if and only if ARG is positive or true.
Note that `strokes-mode' is a global mode.  Think of it as a minor
mode in all buffers when activated.
By default, strokes are invoked with mouse button-2.  You can define
new strokes with

> M-x global-set-stroke

To use strokes for pictographic editing, such as Chinese/Japanese, use
Sh-button-2, which draws strokes and inserts them.  Encode/decode your
strokes with

> M-x strokes-encode-buffer
> M-x strokes-decode-buffer"
  (interactive "P")
  (let ((on-p (if arg
                  (> (prefix-numeric-value arg) 0)
                (not strokes-mode))))
    (cond ((not (display-mouse-p))
           (error "Can't use strokes without a mouse"))
          (on-p                         ; turn on strokes
           (and (file-exists-p strokes-file)
                (null strokes-global-map)
                (strokes-load-user-strokes))
           (add-hook 'kill-emacs-query-functions
                     'strokes-prompt-user-save-strokes)
           (add-hook 'select-frame-hook
                     'strokes-update-window-configuration)
           (strokes-update-window-configuration)
           (define-key global-map [(down-mouse-2)] 'strokes-do-stroke)
           (define-key global-map [(meta down-mouse-2)] 'strokes-do-stroke)
           ;;      (define-key global-map [(control down-mouse-2)] 'strokes-do-complex-stroke)
           (ad-activate-regexp "^strokes-") ; advise button2 commands
           (setq strokes-mode t))
          (t                            ; turn off strokes
           (if (get-buffer strokes-buffer-name)
               (kill-buffer (get-buffer strokes-buffer-name)))
           (remove-hook 'select-frame-hook
                        'strokes-update-window-configuration)
           (if (string-match "^strokes-" (symbol-name (key-binding [(down-mouse-2)])))
               (define-key global-map [(down-mouse-2)] strokes-click-command))
           (if (string-match "^strokes-" (symbol-name (key-binding [(meta down-mouse-2)])))
               (global-unset-key [(meta button2)]))
           ;;      (if (string-match "^strokes-" (symbol-name (key-binding [(shift button2)]))) 
           ;;          (global-unset-key [(shift button2)]))
           (ad-deactivate-regexp "^strokes-") ; unadvise strokes-button2 commands
           (setq strokes-mode nil))))
  (force-mode-line-update))

(or (assq 'strokes-mode minor-mode-alist)
    (setq minor-mode-alist (cons (list 'strokes-mode strokes-modeline-string)
                                 minor-mode-alist)))

(provide 'strokes)
(run-hooks 'strokes-load-hook)

;;; strokes.el ends here